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From: Holger Mauermann <mauermann@gmail.com>
To: linux-raid@vger.kernel.org
Subject: LVM on raid10,f2 performance issues
Date: Mon, 01 Dec 2008 01:00:32 +0100	[thread overview]
Message-ID: <49332920.5010503@gmail.com> (raw)

When I setup LVM on top of a 4 disk RAID 10 with f2 layout read/write
performance is really worse - it's far below single drive speed...

I did some testing with dd and hexdump and I noticed that after writing
a 128k file (with 64k "X" and 64k "Y") to the lvol the data on the raw
disks looks somewhat weird:

sda:  sdb:  sdc:  sdd:
----------------------
YYYY  ....  ....  XXXX
....  ....  ....  ....
XXXX  YYYY  ....  ....
....  ....  ....  ....

Any hints how to tune this? With LVM on a standard RAID 10 (n2) the data
appears as expected on the disks:

sda:  sdb:  sdc:  sdd:
----------------------
YYYY  YYYY  XXXX  XXXX
....  ....  ....  ....
....  ....  ....  ....
....  ....  ....  ....



             reply	other threads:[~2008-12-01  0:00 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-01  0:00 Holger Mauermann [this message]
2008-12-01 16:42 ` LVM on raid10,f2 performance issues Keld Jørn Simonsen
2008-12-02 23:28   ` Holger Mauermann
2008-12-03  7:15     ` Keld Jørn Simonsen
2008-12-03  9:43     ` Michal Soltys
2009-01-19  1:24       ` thomas62186218
2009-01-19  7:28         ` Peter Rabbitson
2009-01-26 19:06           ` Bill Davidsen
2009-01-19  7:30         ` Michal Soltys
2009-01-19 12:17         ` Keld Jørn Simonsen
2009-01-19 12:24           ` Peter Rabbitson
2009-01-19 13:59             ` Keld Jørn Simonsen

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